Method for performing knee surgery and retractors for use therein

ABSTRACT

A method of performing knee surgery and retractors and a femoral distractor for use in performing such method are provided, said retractors including a PCL tibial retractor, lateral patellar retractor, collateral ligament retractor, posterior cruciate ligament retractor and unicompartmental retractor designed to cooperate with one another in performing such method.

BACKGROUND OF THE INVENTION

In performing knee surgery it is of the utmost importance to avoid or atleast minimize damage to ligaments, tendons, muscles, nerves and otherportions of the soft tissue while gaining access to and performingsurgical procedures on various portions of bone structure of the knee.Heretofore, the retractors utilized in performing knee surgery have notbeen specifically tailored to permit maximum access to the bonestructure intended for osteotomy procedures while at the same timeproviding maximum protection for various soft tissue members.

U.S. Pat. No. 4,820,797 discloses a collateral ligament retractor foruse in knee surgery. Such retractor includes a member having a cuppedarcuate finger for insertion into the knee joint along and partly aroundthe tibial plateau and a curved portion extending from the fingeroutwardly around the ligament, then extending back substantially in thesame direction as the finger and including a downwardly extendingpivoted elongated arm extending to a position behind the knee above thecalf. A second member of similar design but larger to accomodate theeverted patella is positioned around the opposite ligament and a tensionmember such as a coil spring is connected to the outer end of the armsof the members for biasing them toward one another to hold the ligamentsin a retracted position.

Patentschrift No. DD-215-468-A of the Duetsche Demokratische Republicdiscloses a wound retractor for knee surgery which has a holder having ahook-shaped convex blade at the distal end.

U.S. Pat. No. 2,695,607 discloses a surgical retractor intended to holdback flesh and muscles from a bone on which surgical treatment is to beperformed.

Zimmer Company, Warsaw, Ind., Catalog for 1966 discloses on page 117 aBlount Knee Retractor having a handle with a tip disposed at an angle ofmore than 90° which is intended to be inserted into the knee joint justproximal to the cartilage so as to expose the line of disection whilebroadening out to retract the superficial soft tissue without use of anadditional retractor.

None of the retractors disclosed in the above referenced prior art orany other retractors known to the applicant have the capability ofproviding the degree of protection as those of the present invention andno prior art surgical procedures for knee surgery are as effective inpermitting access to the bone structure upon which osteotomy proceduresare to be performed while providing protection to the critical softtissue.

SUMMARY OF THE INVENTION

The present invention relates to a method of performing knee surgery andto retractors and a femoral distractor for use in performing suchsurgery.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view showing a step in the knee surgery showinguse of the PCL tibial retractor of the present invention.

FIG. 2 is a perspective view similar to FIG. 1 showing the PCL tibialretractor and the lateral patellar retractor of the present invention inuse during surgery.

FIG. 3 is a perspective view looking from the side of a knee duringsurgery and showing the step of using a posterior cruciate ligamentretractor and a collateral ligament retractor according to the presentinvention.

FIG. 4 is a perspective view taken from the front of a knee duringsurgery showing the step of using the lateral patellar retractor, theposterior cruciate ligament retractor and the collateral ligamentretractor.

FIGS. 5 and 6 are perspective views from different angles showing theuse of the femoral distractor portion of the present invention.

FIG. 7 is a perspective view taken from the front showing the step ofusing unicompartmental retractor in combination with the lateralpatellar retractor.

FIG. 8 is a top plan view of the PCL tibial retractor.

FIG. 9 is a sectional view taken along line 9--9 of FIG. 8.

FIG. 10 is a top plan view of the lateral patellar retractor of thepresent invention.

FIG. 11 is an elevational view of the lateral patellar retractor asshown in FIG. 10.

FIG. 12 is a fragmentary plan view of the retracting end of the lateralpatellar retractor shown in FIG. 10 with such end rotated for clarity.

FIG. 13 is a top plan view of the posterior cruciate ligament retractorof the present invention.

FIG. 14 is a side elevational view of the posterior cruciate ligamentretractor as shown in FIG. 13.

FIG. 15 is a sectional view taken through line 15--15 of FIG. 14.

FIG. 16 is a top plan view of the collateral ligament retractor of thepresent invention.

FIG. 17 is an elevational view of the collateral ligament retractor asshown in FIG. 16.

FIG. 18 is a top plan view, partly in section, of the femoral distractorof the present invention.

FIG. 19 is an elevational view of the femoral distractor as shown inFIG. 18.

FIG. 20 is a sectional view taken through line 20--20 of FIG. 18.

FIG. 21 is a top plan view of the unicompartmental retractor of thepresent invention.

FIG. 22 is an elevational view of the unicompartmental retractor asshown in FIG. 21.

DETAILED DESCRIPTION OF THE INVENTION

Referring to FIGS. 1-7, there is shown a knee generally designated bythe letter K in which an incision has been made through the skin andflesh 11 to expose the interior members upon which osteotomy and otherprocedures are to be performed. Such other procedures may includefitment and placement of an artificial knee prosthesis. Once suchprosthesis is shown and described in the brochure published by Johnson &Johnson Orthopaedics, New Brunswick, N.J., in September 1988 entitled"P.F.C. TOTAL KNEE SYSTEM" ("P.F.C." is a registered trademark ofJohnson & Johnson Orthopaedics Inc.) using a surgical techniquedescribed in a booklet published by Johnson & Johnson Products Inc.entitled "Surgical Technique--The Press Fit Condylar Total Knee SystemWith Specialist Instrument". Although retractors will obviously be usedthroughout the entire surgical procedure of implanting any suchprosthesis, the retractors and method defined by the present inventionare directed primarily to preparation of various portions of the bonestructure for receiving any such prosthesis and protection of theligaments, tendons, muscles, nerves and other critical soft tissuemembers during osteotomy and other procedures.

As shown in FIGS. 1-7, the incision in the knee K permits access to thetibial plateau 12 including lateral and medial tibial condyles 13 and14, respectively. With knee bent as shown in FIGS. 1-7 there is alsoexposed the distal femur 16 including lateral and medial femoralcondyles 17 and 18, respectively. The intercondylar notch (femoraltrochlear groove) 19 separates the lateral and medial femoral condyles17 and 18, respectively. The posterior cruciate ligament 20 is attachedto the femur and tibia proximally and distally, respectively, and needsto be completely protected during the osteotomy.

FIGS. 2, 5 and 6 show the distal femur 16 following condylar osteotomiesincluding distal femoral 2, anterior 3, posterior 4 and chamfer 5 cutswhile FIG. 3 shows the position of the blade 6 of an oscillating saw 7,cutting guide 8 and PCL and collateral ligament retractors to bedescribed hereinafter during posterior 4 femoral osteotomy. Also shownin FIG. 3 is the fibular (lateral collateral) ligament 25 which extendsfrom the lateral aspect 27 of the lateral femoral condyle 17 to the headof the fibula (not shown). Additionally, as shown in FIG. 7, thecollateral ligament 27, including its surrounding capsule is alsoexposed and needs to be protected during unilateral proximal tibialosteotomy.

Referring now to FIGS. 1, 2, 8 and 9, there is provided a PCL tibialretractor 30 which will be described as manufactured and as used in thesurgical method herein. The PCL tibial retractor 30 includes a handle 31which has generally flat upper and lower parallel surfaces 32 and 33,respectively, and edges 34 and 35 which taper inwardly toward each otherand toward a longitudinal axis 36 from an area of maximum breadthadjacent an arcuate free end 37. The handle 31 may have one or moreholes 39 to provide a place for hooking a weight thereto.

Integrally formed with the handle 31 is an integral support section 38from which extend a pair of integral prongs 40. The support section 38and prongs 40 will be described with the handle 31 oriented in ahorizontal position. With the handle 31 so positioned, the supportsection 38 and prongs 40 will have an upper surface 32' and a lowersurface 33' following a gentle S-shaped curve such that the supportsection 38 follows a curve 41 downwardly from horizontal and the prongs40 follow a reverse curve 42 having a radius of curvature substantiallythe same as that of the support section and extending to ends 43 whichare angled upwardly toward such horizontal plane at an angle of about5°+/-2°. The lower surface 33' of the curved portion 41 has a radius ofcurvature of 3.312 inches +/-0.5 inch with its center located 3.312inches below the lower surface 33 of the handle 31 and 3.312 inchesbehind the ends 43. The upper surface 32' of the curved portion 42 has aradius of curvature of 3.312 inches +/-0.5 inch with its center located2.625 inches above the upper surface 32 of the handle 31 and 0.400 inchbehind the ends 43. If desired, there could be a short planar segmentseparating the curved portion 41 from the reverse curve 42.

The PCL tibial retractor as shown in FIG. 9 has a uniform thickness of0.120 inch throughout except for the last 0.5 inch of the prongs 40adjacent the ends 43 each of which tapers to a thickness of 0.030 inch+/-0.010 inch at the ends 43. The thickness and shape of the handle arenot critical; however, the handle must be sufficiently rigid to preventexcessive bending during use and must have a shape which is convenientto use without obstructing desired surgical procedures when in use.

Referring now to FIG. 8, the support section 38 includes edges 34' and35' which taper inwardly toward a vertical plane lying on thelongitudinal axis 36 to a point of minimum breadth just before thejuncture between the support section 38 and the prongs 40. This areashould have a breadth of 0.430 inch +/-0.020 inch in order that it canfit within the intercondylar notch 19 of the femurs and to use thatportion as a fulcrum without damaging it. If desired, the supportsection 38 could have parallel edges 34' and 35' spaced apart suchdistance, in which case, such edges would flare outwardly at theirrespective junctures with the handle 31.

As can also be seen in FIG. 8, the edges 34' and 35' join with the outeredges 34" and 35", respectively, of the prongs 40. Such outer edges 34"and 35" follow a straight line path parallel to such vertical planelying on the longitudinal axis 36 and are spaced apart 0.770 inch+/-0.020 inch.

The prongs 40 have inner edges 48 and 49 which follow a straight linepath in the area of juncture with said integral support section 38 andwhich taper outwardly from said vertical plane at angle of 5° for the0.5 inch portion adjacent the respective ends 43. The distance betweenthe inner edges 48 and 49 in the straight line portion of the prongs is0.430 inch +/-0.020 inch. The ends 43 are rounded with the respectivetips having a breadth of 0.030 inch +/-0.010 inch. The inner edges 48and 49 are joined by an arcuate segment 47, preferably having a radiusof at least 0.215 inch.

As can be seen in FIGS. 1 and 2, the size, shape and space between theprongs 40 permit the prongs to straddle and thus protect the posteriorcruciate ligament 20 and for the portions adjacent the ends 43 to restagainst the posterior side of the respective lateral tibial condyle 13and medial tibial condyle 14. The PCL tibial retractor 30 may then bemoved in a direction toward the patient as indicated by the arrow 48thus using the intercondylar notch 19 as a fulcrum. Such positioningpresents the surfaces of the lateral tibial condyle 13 and medial tibialcondyle 14 for osteotomy.

Referring now to FIGS. 2, 10, 11 and 12, there is shown a lateralpatellar retractor 50 which includes a handle 51 having a longitudinalaxis 56 and having generally flat upper and lower parallel surfaces 52and 53, respectively, and edges 54 and 55. As may be seen in FIG. 10,the edges 54 and 55 are parallel to one another and to the longitudinalaxis 56 in the area extending to an arcuate free end 57. The handle hasone or more apetures 59 through which weighted hooks may be placed if itis desired to retain the retractor in position without a personattending thereto. Integrally formed with the handle 51 is a flat planarsupport section 58 which is disposed at an angle downwardly ofapproximately 55° from horizontal when the handle 51 is oriented in ahorizontal position. Such angle could vary by as much as +/-30°. Anarcuate section 61 joins the support section 58 to the handle 51.

Approximately one-third of the way between the free end 57 and thearcuate section 61, the edges 54 and 55 taper inwardly toward thelongitudinal axis 56 at an angle of approximately 4°. The edges 54 and55 continue to taper inwardly toward such longitudinal axis until theyreach a point of minimum breadth 60. As can be seen in FIGS. 10 and 12,the support section 58 has edges 54' and 55' which are parallel to eachother and to a vertical plane lying on the longitudinal axis. Preferablythe distance between such edges is about 0.71 inch; however, since itsfunction is primarily to move the incised soft tissue away from thelateral tibial condyle 13 (see FIG. 2), it could be broader or somewhatnarrower and the edges 54' and 55' are not required to be straight.

Integrally formed with and extending from the support section 58 arethree prongs including a pair of side prongs 63 and a center prong 64.As can be seen from the drawings, the center prong 64 extends beyond theends of the two side prongs 63. The prongs 63 and 64 are joined to theplanar portion of the support section 58 and, as may be seen in FIG. 11have upper and lower surfaces 52" and 53" which initially follow astraight line path and terminate in an arcuate path. The arcuate pathhas a radius of 1.62 inch +/-0.5 inch to the upper surface 52" with acenter located 1.19 inch below the plane defined by the upper surface 52of the handle 51 and 0.54 inch beyond the end of the center prong 64.The segment of the prongs 63 and 64 following a straight line path isapproximately 0.35 inch while the overall length of the side prongs 63including the portion with the straight line segment is 1.07 inch+/-0.020 inch while the overall length of the center prong 64 is 1.32inch +/-0.020 inch. Thus, the center prong 64 extends beyond the prongs63 by 0.25 inch.

The side prongs 63 have outer edges 54" and 55" each of which, for about0.35 inch, are extensions of and lie in the same path followed by theedges 54' and 55', respectively, of the adjacent portion of the supportsection 58. Each of the side prongs 63 has an inner edge 65 which, forabout 0.35 inch, is parallel to the vertical plane extending through thelongitudinal axis 56. The center prong 64 has a pair of edges 67, eachof which, for about 0.35 inch, is spaced from and parallel to the firstportion of the inner edges 65.

The end portions of each of the prongs 63 and 64 taper to rounded tipshaving a radius of 0.03 inch +/-0.010 inch in both the horizontal andvertical planes. Thus, as can be seen in FIG. 12, the edges 54" and 65;and 55" and 65 of each of the side prongs 63, for a distance ofapproximately 0.72 inch their respective ends are disposed at an angleof approximately 16° to each other. Similarly, the edges 67 of thecenter prong 64 for a distance of approximately 0.97 inch from its endare disposed at an angle of approximately 16° to each other.

The distance between the outer edges 54" and 55" of the side prongs 63is 0.71 inch +/-0.020 inch in the area parallel to the vertical planeextending through the longitudinal axis 56 with each of such prongshaving a breadth in that area of 0.18 inch. The breadth of the centerprong 64 in that area in which the edges 67 are parallel is 0.20 inch.

The thickness of the lateral patellar retractor 50 is 0.12 inchesthroughout the entire length except for the prongs 63 and 64 which taperat their ends to a thickness of 0.06 inch +/-0.010 inch. The taper inthickness for the side prongs 63 and center prong 64 begins at a point0.35 inch from their respective junctures with the support section 58 asdetermined by the ends of the slots between the prongs. If desired, thelateral patellar retractor 50 could have four prongs with the two centerprongs extending beyond the ends of the two side prongs.

As can be seen in FIG. 2, such construction permits the lateral patellarretractor 50 to be readily inserted along side of the lateral tibialcondyle 13 so that the retractor 50 may use the shelve of such lateraltibial condyle 13 as its restive point. In as much as the center prong64 is longer than the side prongs 63, the insertion may be easilyaccomplished. Such elongated center prong coupled with the curved upperand lower surfaces 52 and 53 at the ends of such center prong 64 andside prong 63 permit the lateral patellar retractor 50 to slide aroundthe lateral tibial condyle with minimum damage to the surrounding softtissue. In particular, such configuration clearly avoids damage to thecommon peroneal nerve, the tibial condyle itself or the attendantlateral soft tissue structures. The broad flat support section 58engages the lateral soft tissue structure as the handle is moved in thedirection indicated by the arrow 9. Thus, when the lateral patellarretractor 50 is in such position and the PCL tibial retractor 30 ispositioned as described in FIG. 1 and as shown in FIG. 2, there isprovided an unimpeded presentation of the tibial plateau 12 includingthe lateral tibial condyle 13 and medial tibial condyle 14 with theprepared distal femoral surface 16 held safely clear of the field toallow accurate tibial osteotomy.

Referring now to FIGS. 3, 4 and 13-17, there is shown a posteriorcruciate ligament retractor 70 and collateral ligament retractor 90. Theposterior cruciate ligament retractor 70 includes a handle 71 which hasgenerally flat upper and lower parallel surfaces 72 and 73,respectively, and edges 74 and 75 which taper inwardly toward the eachother and toward a longitudinal axis 76 from an area of maximum breadthadjacent an arcuate free end 77. The handle 71 may have one or moreholes 89 to provide a place for hooking a weight thereto. The handle 71merges into an integral support section 78 having edges 74' and 75'. Theedges 74' and 75' are parallel to a vertical plane passing through thelongitudinal axis 76 assuming that the portion of the handle 71 in thearea of the free end 77 is in a horizontal position.

As can be seen from FIG. 15, the support section 78 has upper and lowersurfaces 79 and 80, respectively, each of which has an arcuateconfiguration extending from edge 74' to edge 75'. Such arcuateconfiguration is not critical and one or both of such surfaces 79 and 80could be flat. The distance between the edges 74' and 75' of theintegral support section 78 is 0.43 inch +/-0.020 inch and the thicknessin the center of such support section 78 and the handle 71 is about 0.12inch. The thickness and shape of the handle 71 and support section 78are not critical; however, they must be sufficiently rigid to preventexcessive bending during use and must have a shape which functions toretract and protect the appropriate soft tissue without obstructingdesired surgical procedures when in use.

The handle 71 curves downwardly in an arcuate path with the lowersurface 73 extending through an arc of 22° with a radius of 5.0 inch+/-0.5 inch. The integral support section 78 extends in a generallystraight line path downwardly at an angle of 22° +/-1.5° fromhorizontal.

A tip 81 is integrally formed with and extends from the integral supportsection 78 to an end 84. The tip 81 has upper and lower surfaces 82 and83 which follow an arcuate path reversed from the arcuate path of thehandle 71 with the upper surface 82 having a radius of 2.0 inch +/-0.4inch with a center of radius located 0.78 inch above a plane defined bythe upper surface 72 of the handle 71 and approximately 0.18 inch behindthe end 84 of the tip 81. The length of the tip 81 from the supportsection 78 to the end 84 is 1.10 inch +/-0.020 inch. The end 84 and theportion of the tip 81 adjacent thereto are angled upwardly towardhorizontal. The tip 81 has edges 85 and 86 which taper at an angle of 4°+/-1° to a vertical plane passing through the longitudinal axis(included angle equals 8° +/-2°). Each of the edges 85 and 86 flaresoutwardly through arcuate sections 87 and 88, respectively, in the areawhere the tip 81 merges with the support section 78. The edges 85 and 86extend to the end 84 which is defined by an arcuate path having a radiusof 0.05 inch +/-0.01 inch.

The thickness of the tip 81 tapers from 0.12 inch at the support section78 to 0.045 inch +/-0.010 inch at the end 84. The end is rounded fromthe lower surface 83 to the upper surface 82 with a radius of 0.04 inch+/-0.01 inch.

Referring now to FIGS. 16 and 17, the collateral ligament retractor 90includes a handle 91 which has generally flat upper and lower parallelsurfaces 92 and 93, respectively, and edges 94 and 95. The edges 94 and95 are generally parallel in the area adjacent an arcuate free end 96.The handle 91 may have one or more holes 109 to provide a place forhooking weights thereto. At any desired point, the edges 94 and 95 tapertoward a longitudinal axis 97. The handle 91 merges into an integralsupport section 98. The integral support section 98 includes upper andlower surfaces 99 and 100, respectively, which curve downwardlyfollowing a curved path through an arc of approximately 28° on a radiusof approximately 1.25 inches from the lower surface 100. The supportsection 98 has edges 101 and 102 which follow a straight line pathparallel to a vertical plane passing through the longitudinal axis 97and flare outwardly where they are joined to edges 94 and 95,respectively, of the handle 91. The breadth of the support section 98 inthe area in which the edges 101 and 102 follow a straight line path is0.24 inch +/-0.020 inch.

A tip 103 extends from the integral support section 98 to a blunt freeend 106. The tip 103 has upper and lower surfaces 104 and 105,respectively, which follow a curved path through an arc of 44.5° +/-0.5°and having a radius of 3.0 inches, the center of which is 2.5 inches+/-0.5 inch above a horizontal plane defined by the upper surface 92 ofthe handle and positioned 0.88 inch behind the end 106 of the tip 103.Thus, as can be seen, the tip 103 has its end 106 pointed slightlyupwardly toward the horizontal plane defined by the upper surface 92;however, it does not extend up to such plane. At its lowest point, thetip 106 is approximately 0.59 inch below such horizontal plane.

The tip 103 has edges 107 and 108, respectively, which taper inwardlytoward a vertical plane passing through the longitudinal axis 97 at anangle of 4° +/-1° and joining the end 106 which has a radius of 0.125inch +/-0.010 inch. Thus the included angle between the edges is 8°+/-2°. The tip 103 has a maximum breadth 0.41 inch +/-0.02 inch located1.93 inch from the end 106. The breadth near the end 106 at the point ofjuncture between the straight line segment of the edges 107 and 108 andthe arcuate tip is 0.25 inch +/-0.02 inch.

The collateral ligament retractor 90 has a thickness of 0.12 inchthroughout the handle portion 91 and the integral support section 98 andtapers to a thickness of 0.09 inch +/-0.02 inch at the end 106 with theend rounded in the vertical direction on a radius of 0.045 inch +/-0.01inch. The thickness and shape of the handle 91 and the thickness of thesupport section 98 are not critical; however, they must be sufficientlyrigid to prevent excessive bending when in use and must have a shapewhich functions to retract and protect the appropriate soft tissuewithout obstructing surgical procedures when in use.

Referring now to FIGS. 5, 6 and 18-20, there is shown a femoraldistractor 120 for use in providing traction to the femur duringsurgery. Such distraction opens the joint to enhance visualization ofthe posterior capsule and facilitate removal of osteophytes, loosebodies and residual meniscal tissue. Such distraction also assists inaccruate evaluation of the flexain gap. The femoral distractor 120 ofthe present invention permits the surgeon to provide maximum tractionwith minimized possibility of damage and ease of insertion into themedullary canal of the femur and includes vent means provided to relievepressure during such insertion.

The femoral distractor 120 includes an insertion rod 121 following astraight line path along a longitudinal axis 122, a generally U-shapedsupport rod 123 integrally formed therewith and a handle 124 joined tosupport rod 123 along a second longitudinal axis 125 parallel to andspaced from the longitudinal axis 122.

The insertion rod 121 may have a circular cross-sectional configurationbut preferably has a cross-sectional configuration such as that shown inFIG. 20, which can best be described as a circular cross-sectionalconfiguration from which a chordal segment has been removed to provide aflat planar surface 126 in the area facing toward the handle 124.

The insertion rod 121 is also provided with a longitudinal groove 127extending parallel to the longitudinal axis 122 from a rounded free end128 to the juncture of the insertion rod 121 with the support rod 123.The groove 127 is positioned opposite the flat planar face 126 andprovides a vent passageway to relieve pressure as the insertion rod isinserted into the medullary canal of the femur.

A significant feature of the femoral distractor 120 of the presentinvention resides in the configuration of the support rod 123 in thearea of its juncture with the insertion rod 121. Thus, as shown mostclearly in FIG. 18, a major portion 123A of the support rod 123 isdisposed at an angle of 90° to the respective longitudinal axes 122 and125. The portion forming the corner 123B initially follows an arcuatepath in a direction away from both of said longitudinal axes 122 and 125followed by a reverse curved portion joining it to the major portion123A. Such construction permits the surgeon to apply the needed pressurerequired for maximum distraction under the circumstances while ensuringagainst undue pressure being placed against that portion of the femuradjacent the entry point of insertion into the medullary canal. Thus,construction of the support rod 123 with the outwardly bent corner 123Bwhich initially extends away from the longitudinal axis 125 on which thehandle is placed appears to provide for a more uniform distribution ofthe stresses over a large portion of the femur during distraction. Incontrast, a distractor which follows a simple arcuate 90° path from theinsertion rod to the support rod appears to concentrate excessivepressure at that portion of the femur immediately adjacent the point ofinsertion into the medullary canal. Such excessive pressure may alsooccur when distraction is performed by lifting the protruding end of astraight insertion rod which had been placed in the medullary canal.

Referring now to FIGS. 7, 21 and 22, there is provided aunicompartmental retractor 140 which is designed as a shield to protectthe collateral ligament 27 and posterior structures during unilateralproximal tibial osteotomy.

The unicompartmental retractor includes a handle 141 which has generallyflat upper and lower parallel surfaces 142 and 143, respectively, andedges 144 and 145. The edges 144 and 145 are generally parallel in thearea adjacent an arcuate free end 146. The handle 141 may have one ormore holes 147 to provide a place for hooking weights thereto. At anydesired point, the edges 144 and 145 may taper toward a longitudinalaxis 148.

Extending from the handle is an integral tip 150 having edges 144' and145' which continue to taper toward a vertical plane passing through thelongitudinal axis 148 (assuming the handle 141 is positioned with theupper and lower surfaces 142 and 143 in a horizontal plane). The tip 150has upper and lower sufaces 142' and 143', respectively, which initiallyfollow a straight line angled path downwardly from the handle 141 at anangle of approximately 45° +/-1.5°. It then joins with an arcuateportion where it curves upwardly on a radius of 1.5 inches +/-0.2 inch.The center of radius of such arc is positioned 0.35 inch +/-0.2 inchabove the plane defined by the upper surface 142 of the handle and 2.26inches +/-0.05 inch forward of the juncture of the tip 150 with thehandle 141. The arcuate section of the tip 150 has extending therefrom ashort straight segment 151, 0.30 inch +/-0.02 inch in length, which isdisposed at an angle of 5° +/-2° from vertical in a direction away fromsaid handle 141 and terminates in an end 152 approximately 0.10 inchbelow the plane of the upper surface 142. The end 152 has a breadth of0.30 inch+/-0.020 inch and perferably is rounded from the surface 142'to the surface 143'.

The handle 141 and the tip 150 up to approximately its lowest point ofthe arcuate section have a thickness of approximately 0.12 inch.However, the thickness in that area is not critical provided it is rigidenough to prevent excessive bending during use. From such lowest pointto the end the thickness of the tip 150 tapers with a thickness at theend 152 of 0.060 inch +/-0.020 inch.

The angle of taper of the edges 144' and 145' is 5° +/-1° from avertical plane passing through the longitudinal axis 148 for a totalincluded angle of 10° +/-2°.

In conducting the surgical procedure according to the method of thepresent invention, following incision of the knee K, the PCL tibialretractor 30 is inserted carefully between the distal femur 16 and thetibial plateau 12 with the prongs straddling on opposite sides of theposterior cruciate ligament 20 with the ends 43 of the prongs 40 restingagainst the posterior side of the lateral tibial condyle 13 and medialtibial condyle 14, respectively. The support section 38 of the PCLtibial retractor rests against the intercondylar notch 19 which acts asa fulcrum as the handle 31 is moved in the direction indicated by thearrow 48.

The lateral patellar retractor 50 is then inserted using the elongatedcenter prong 64 as the lead along the lateral aspect of the lateraltibial condyle 13 with the support section 58 moving the adjacent softtissue away from the incision to permit tibial osteotomy without riskingdamage to the surrounding soft tissue. After performing osteotomy on thetibial plateau, namely, the lateral tibial condyle 13 and medial tibialcondyle 14, the posterior cruciate ligament retractor 70 is inserted onthe medial side of the medial femoral condyle 18 while the collateralligament retractor 90 is passed around the opposite side of such medialfemoral condyle 18 meeting posteriorly to form a protective arc toprotect the ligaments and hold them clear of the blade of theoscillating saw during osteotomy of the posterior portion of the medialfemoral condyle 18. The instruments are reversed and placed around thelateral femoral condyle 17 during posterior osteotomy of such lateralfemoral condyle.

The unicompartmental retractor 140 is inserted around the side andposterior aspect of the tibial condyle, either the lateral tibialcondyle 13 or medial tibial condyle 14, in order to protect thecollateral ligament and posterior structures during unilateral proximaltibial osteotomy.

The invention disclosed herein provides new and novel surgicalinstruments in the form of retractors and femoral distractor whichprovide maximum protection to critical soft tissue members duringosteotomy and other procedures and permit new and effective surgicalprocedures to be performed.

I claim:
 1. A method of performing knee surgery comprising the stepsof:(a) incising exterior portions of the knee to gain access to theinterior: (b)(i) inserting a PCL tibial retractor having two prongs ofequal length extending from a common support into the incised kneeagainst the posterior tibial condyles with said prongs being positionedon opposite sides of the posterior cruciate ligament; (ii) applyingleverage to said posterior tibial condyles by moving said PCL tibialretractor to a position at which said common support engages theintercondylar groove of the femur, applying leverage to said commonsupport so that the intercondylar groove acts as a fulcrum in causingthe prongs to move the posterior tibial condyles; (c)(i) inserting alateral patellar retractor having three prongs extending from a commonsupport into the incised knee, the middle one of said three prongsextending beyond the ends of the other two of said three prongs, atleast one of said three prongs engaging the laterial tibial condyle andthe common support engaging the incised soft tissue; (ii) moving saidcommon support laterally against said soft tissue while said lateraltibial condyle is engaged by at least one of said three prongs; and, (d)performing tibial osteotomy while said PCL tibial retractor and saidlateral patellar retractor are positioned as set forth in steps (b) and(c), respectively.
 2. A method of performing knee surgery comprising thesteps of:(a) incising exterior portions of the knee to gain access tothe interior; (b)(i) inserting a PCL tibial retractor having two prongsof equal length extending from a common support into the incised kneeagainst the posterior tibial condyles with said prongs being positionedon opposite sides of the posterior cruciate ligament; (ii) applyingleverage to said posterior tibial condyles by moving said tibialretractor to a position at which said common support engages theintercondylar groove of the femur, applying leverage to said commonsupport so that the intercondylar groove acts as a fulcrum in causingthe prongs to move the posterior tibial condyles; (c)(i) inserting alateral patellar retractor having three prongs extending from a commonsupport into the incised knee, the middle one of said three prongsextending beyond the ends of the other two of said three prongs, atleast one of said three prongs engaging the laterial tibial condyle andthe common support engaging the incised soft tissue; (ii) moving saidcommon support laterally against said soft tissue while said lateraltibial condyle is engaged by at least one of said three prongs; (d)performing tibial osteotomy while said PCL tibial retractor and saidlateral patellar retractor are positioned as set forth in steps (b) and(c), respectively; (e) inserting a posterior cruciate ligament retractorhaving(i) a handle extending along a longitudinal axis; (ii) an integralsupport extending downwardly from said handle when the portion of saidhandle adjacent thereto is positioned in a horizontal plane andfollowing initially a curved path and then a straight line path; and(iii) an integral tip extending from said integral support and followinga curved path which is reverse in direction to the curved path of saidintegral support, said integral tip having edges tapering toward avertical plane lying on said longitudinal axis and terminating in apointed free end; into the incised knee in the space between the twocondyles with integral tip extending to the posterior side of saidcondyle; and, (f) inserting a collateral ligament retractor having(i) ahandle extending along a longitudinal axis; (ii) an integral supportextending from said handle and following a curved path downwardly whenthe portion of said handle adjacent thereto is in a horizontal plane;and (iii) a tip extending from said integral support section andfollowing a curved path in a reverse direction from that of saidintegral support section to an end segment directed upwardly toward butbelow said horizontal plane; into the incised knee on the opposite sideof said condyle from said posterior cruciate ligament retractor andcooperating therewith to form a protective arc around said condyle; and(g) moving the pointed free end of said posterior cruciate ligamentretractor and the end segment of said collateral ligament retractor intoclose proximity with each other on the posterior side of said condyleand moving their respective handles apart to(i) form a protective arcaround said condyle; (ii) move ligaments of the knee away from theposterior femoral portion of said condyle; and, (h) performing osteotomyon said posterior femoral portion of said condyle.
 3. A posteriorcruciate tibial retractor for use in performing knee surgerycomprising:(a) a handle, at least a portion of which extends along alongitudinal axis; (b) an integral support having upper and lowersurfaces curving downwardly from said handle portion along a firstcurved path when said handle portion is positioned in a horizontal planesaid first curved path having a radius of curvature of predeterminedlength, said integral support extending in a direction aligned with butcurving downwardly from said longitudinal axis and having spaced apartedges defining an area of minimum breadth sized to fit in theintercondylar notch of the femur of a human adult and to use suchintercondylar notch as a fulcrum without damaging it; and, (c) a pair ofspaced apart prongs of equal length extending from said integralsupport, said prongs having outer edges flaring outwardly from said areaof minimum breadth and having upper and lower surfaces following asecond curved path reverse of said first curved path of said integralsupport said second curved path having a radius of curvaturesubstantially equal in length to said predetermined length, said prongsterminating at rounded end portions spaced below but angled upwardlytoward said horizontal plane, said prongs having inner and outer edges,said outer edges being parallel to each other and each of said inneredges having a major portion adjacent said integral support parallel toeach other and a minor portion extending to said end portions disposedat an angle tapering toward its respective outer edge, said inner edgesbeing spaced apart a distance which permits said prongs to straddle andprotect the posterior cruciate ligament and said end portions to engagethe posterior side of the tibial condyles when the integral support ispositioned in the intercondylar notch.
 4. A posterior cruciate tibialretractor for use in performing knee surgery comprising:(a) a handle, atleast a portion of which extends along a longitudinal axis; (b) anintegral support curving downwardly from said handle portion when saidhandle portion is positioned in a horizontal plane along a curve havinga radius of predetermined length, said integral support having an areawith a predetermined breadth sized to fit within the intercondylar notchof the femur of a human adult, and to use such intercondylar notch as afulcrum without damaging it; and, (c) a pair of spaced apart prongsfollowing a reverse curve having a radius equal to said predeterminedlength and extending from said integral support to end portions angledupwardly, said prongs sized to straddle and protect the posteriorcruciate ligament and said end portions to engaged the posterior side ofthe tibial condyles when the integral support is positioned in theintercondylar notch.
 5. A posterior cruciate tibial retractor accordingto claim 4, wherein the end portions of said prongs are disposed at anangle of approximately 5° to horizontal when said handle portion ispositioned in a horizontal plane.
 6. A posterior cruciate tibialretractor according to claim 5, wherein the overall width of said prongsis 0.77 inch +/-0.02 inch, the space between said prongs is 0.43 inch+/-0.02 inch, the breadth of said integral support area is 0.43 inch+/-0.02 inch and the thickness of said end portions is 0.06 inch +/-0.02inch.
 7. A posterior cruciate tibial retractor according to claim 3wherein said predetermined length is equal to 3.312 inches +/-0.5 inch.8. A posterior cruciate tibial retractor according to claim 4 whereinsaid predetermined length is equal to 3.312 inches +/-0.5 inch.
 9. Aposterior cruciate tibial retractor according to claim 5 wherein saidpredetermined length is equal to 3.312 inches +/-0.5 inch.
 10. Aposterior cruciate tibial retractor according to claim 6 wherein saidpredetermined length is equal to 3.312 inches +/-0.5 inch.
 11. Aposterior cruciate tibial retractor according to claims 7, 8, 9, or 10wherein the center of said first curve is located approximately 3.312inches below said handle and approximately 3.312 inches toward thehandle from said prong end portions and the center of said second curveis located approximately 2.62 inches above said handle and approximately0.4 inch toward the handle from prong end portions.
 12. A method ofperforming knee surgery comprising the steps of:(a) incising exteriorportions of the knee to gain access to the interior; (b)(i) inserting aPCL tibial retractor having two spaced apart prongs extending from acommon support into the incised knee against the posterior tibialcondyles with said prongs being positioned on opposite sides of theposterior cruciate ligament; (ii) applying leverage to said posteriortibial condyles by moving said PCL tibial retractor to a position atwhich said common support engages the intercondylar groove of the femur,applying leverage to said common support so that the intercondylargroove acts as a fulcrum in causing the prongs to move the posteriortibial condyles; (c)(i) inserting a lateral patellar retractor having aplurality of spaced apart prongs extending from a common support intothe incised knee, at least one of said lateral patellar retractor prongsengaging the lateral tibial condyle and the common support engaging theincised soft tissue; (ii) moving said common support laterally againstsaid soft tissue while said lateral tibial condyle is engaged by atleast one of said lateral patellar retractor prongs; and (d) performingtibial osteotomy while said PCL tibial retractor and said lateralpatellar retractor are positioned as set forth in steps (b) and (c),respectively.
 13. A method of performing knee surgery comprising thesteps of:(a) incising exterior portions of the knee to gain access tothe interior; (b)(i) inserting a PCL tibial retractor having two spacedapart prongs extending from a common support into the incised kneeagainst the posterior tibial condyles with said prongs being positionedon opposite sides of the posterior cruciate ligament; (ii) applyingleverage to said posterior tibial condyles by moving said tibialretractor to a position at which said common support engages theintercondylar groove of the femur, applying leverage to said commonsupport so that the intercondylar groove acts as a fulcrum in causingthe prongs to move the posterior tibial condyles; (c)(i) inserting alateral patellar retractor having a plurality of spaced apart prongsextending from a common support into the incised knee, at least one ofsaid lateral patellar retractor prongs engaging the lateral tibialcondyle and the common support engaging the incised soft tissue; (ii)moving said common support laterally against said soft tissue while saidlateral tibial condyle is engaged by at least one of said lateralpatellar retractor prongs; (d) performing tibial osteotomy while saidPCL tibial retractor and said lateral patellar retractor are positionedas set forth in steps (b) and (c), respectively; (e) inserting aposterior cruciate ligament retractor having(i) a handle extending alonga longitudinal axis; (ii) an integral support extending downwardly fromsaid handle when the portion of said handle adjacent thereto ispositioned in a horizontal plane and following initially a curved pathand then a straight line path; and (iii) an integral tip extending fromsaid integral support and following a curved path which is reverse indirection to the curved path of said integral support, said integral tiphaving edges tapering toward a vertical plane lying on said longitudinalaxis and terminating in a pointed free end;into the incised knee in thespace between the two condyles with integral tip extending to theposterior side of said condyle; and, (f) inserting a collateral ligamentretractor having(i) a handle extending along a longitudinal axis; (ii)an integral support extending from said handle and following a curvedpath downwardly when the portion of said handle adjacent thereto is in ahorizontal plane; and (iii) a tip extending from said integral supportsection and following a curved path in a reverse direction from that ofsaid integral support section to an end segment directed upwardly towardbut below said horizontal plane; into the incised knee on the oppositeside of said condyle from said posterior cruciate ligament retractor andcooperating therewith to form a protective arc around said condyle; and(g) moving the pointed free end of said posterior cruciate ligamentretractor and the end segment of said collateral ligament retractor intoclose proximity with each other on the posterior side of said condyleand moving their respective handles apart to(i) form a protective arcaround said condyle; (ii) move ligaments of the knee away from theposterior femoral portion of said condyle; and, (h) performing osteotomyon said posterior femoral portion of said condyle.